diff --git a/xsd/NamespaceIdMap.cs b/xsd/NamespaceIdMap.cs
new file mode 100644
index 0000000000..5c0a5b143a
--- /dev/null
+++ b/xsd/NamespaceIdMap.cs
@@ -0,0 +1,420 @@
+// Copied 20190504 from https://github.com/OfficeDev/Open-XML-SDK/blob/master/src/DocumentFormat.OpenXml/Framework/NamespaceIdMap.cs
+
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace DocumentFormat.OpenXml.Framework
+{
+    internal static class NamespaceIdMap
+    {
+        /// <summary>
+        /// A list of namespaces, associated prefixes and the version in which it was introduced.
+        /// </summary>
+        /// <remarks>
+        /// CAUTION: Do NOT modify this list except by adding to the end. The index of the entry is tied
+        /// directly to an id used extensively throughout the SDK. Ideally, this will be updated to not
+        /// have this magic, but that will take time. If any items are updated in the middle of the list,
+        /// the strongly typed schema classes and validation data will need to be regenerated.
+        /// </remarks>
+        private static readonly NamespaceResolver _namespaceResolver = new NamespaceResolver
+        {
+            { string.Empty, string.Empty, FileFormatVersions.None },
+            { "http://www.w3.org/XML/1998/namespace", "xml", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/package/2006/metadata/core-properties", "cp", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/extended-properties", "ap", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/custom-properties", "op", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes", "vt", FileFormatVersions.Office2007 },
+            { "http://purl.org/dc/elements/1.1/", "dc", FileFormatVersions.Office2007 },
+            { "http://purl.org/dc/terms/", "dcterms", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/characteristics", "ac", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/bibliography", "b", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/main", "a", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/chart", "c", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/chartDrawing", "cdr", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/compatibility", "comp", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/diagram", "dgm", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/lockedCanvas", "lc", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing", "wp", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/picture", "pic", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing", "xdr", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/relationships", "r", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/customXml", "ds", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/officeDocument/2006/math", "m", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/spreadsheetml/2006/main", "x", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/wordprocessingml/2006/main", "w", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/presentationml/2006/main", "p", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/schemaLibrary/2006/main", "sl", FileFormatVersions.Office2007 },
+            { "urn:schemas-microsoft-com:vml", "v", FileFormatVersions.Office2007 },
+            { "urn:schemas-microsoft-com:office:office", "o", FileFormatVersions.Office2007 },
+            { "urn:schemas-microsoft-com:office:word", "w10", FileFormatVersions.Office2007 },
+            { "urn:schemas-microsoft-com:office:excel", "xvml", FileFormatVersions.Office2007 },
+            { "urn:schemas-microsoft-com:office:powerpoint", "pvml", FileFormatVersions.Office2007 },
+            { "http://schemas.openxmlformats.org/markup-compatibility/2006", "mc", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/excel/2006/main", "xne", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/word/2006/wordml", "wne", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/01/customui", "mso", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/activeX", "ax", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/coverPageProps", "cppr", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/customDocumentInformationPanel", "cdip", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/metadata/contentType", "ct", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/metadata/customXsn", "ntns", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/metadata/longProperties", "lp", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2006/metadata/properties/metaAttributes", "ma", FileFormatVersions.Office2007 },
+            { "http://www.w3.org/2001/XMLSchema", "xsd", FileFormatVersions.Office2007 },
+            { "http://www.w3.org/2003/InkML", "inkml", FileFormatVersions.Office2007 },
+            { "http://www.w3.org/2003/04/emma", "emma", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/ink/2010/main", "msink", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/drawing/2007/8/2/chart", "c14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2010/chartDrawing", "cdr14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2010/main", "a14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/powerpoint/2010/main", "p14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2010/picture", "pic14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing", "wp14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/word/2010/wordml", "w14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2009/9/main", "x14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/excel/2010/spreadsheetDrawing", "xdr14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac", "x14ac", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2008/diagram", "dsp", FileFormatVersions.Office2007 },
+            { "http://schemas.microsoft.com/office/2009/07/customui", "mso14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2010/diagram", "dgm14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas", "wpc", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/word/2010/wordprocessingGroup", "wpg", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/word/2010/wordprocessingShape", "wps", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2010/slicer", "sle", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2010/compatibility", "com14", FileFormatVersions.Office2010 },
+            { "http://schemas.microsoft.com/office/drawing/2012/chart", "c15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/drawing/2012/chartStyle", "cs", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/webextensions/webextension/2010/11", "we", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/drawing/2012/main", "a15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/powerpoint/2012/main", "p15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/word/2012/wordml", "w15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/webextensions/taskpanes/2010/11", "wetp", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2010/11/main", "x15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2011/1/ac", "x12ac", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/thememl/2012/main", "thm15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2010/11/ac", "x15ac", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/word/2012/wordprocessingDrawing", "wp15", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/powerpoint/2012/roamingSettings", "pRoam", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/drawing/2012/timeslicer", "tsle", FileFormatVersions.Office2013 },
+            { "http://schemas.microsoft.com/office/powerpoint/2015/main", "p16", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/drawing/2014/main", "a16", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/drawing/2014/chartex", "cx", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/drawing/2014/chart/ac", "c16ac", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/drawing/2014/chart", "c16", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2014/revision", "xr", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2014/11/main", "x16", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/spreadsheetml/2015/02/main", "x16r2", FileFormatVersions.Office2016 },
+            { "http://schemas.microsoft.com/office/word/2015/wordml/symex", "w16se", FileFormatVersions.Office2016 },
+        };
+
+        // This dictionary contains the Strict and Transitional namespaces pairs to be interpreted equivalent.
+        private static readonly Dictionary<string, string> _strictTransitionalNamespaces = new Dictionary<string, string>(StringComparer.Ordinal)
+        {
+            // Namespaces
+            { "http://purl.oclc.org/ooxml/descriptions/base", "http://descriptions.openxmlformats.org/description/base" },
+            { "http://purl.oclc.org/ooxml/descriptions/full", "http://descriptions.openxmlformats.org/description/full" },
+            { "http://purl.oclc.org/ooxml/drawingml/chart", "http://schemas.openxmlformats.org/drawingml/2006/chart" },
+            { "http://purl.oclc.org/ooxml/drawingml/chartDrawing", "http://schemas.openxmlformats.org/drawingml/2006/chartDrawing" },
+            { "http://purl.oclc.org/ooxml/drawingml/diagram", "http://schemas.openxmlformats.org/drawingml/2006/diagram" },
+            { "http://purl.oclc.org/ooxml/drawingml/main", "http://schemas.openxmlformats.org/drawingml/2006/main" },
+            { "http://purl.oclc.org/ooxml/drawingml/picture", "http://schemas.openxmlformats.org/drawingml/2006/picture" },
+            { "http://purl.oclc.org/ooxml/drawingml/spreadsheetDrawing", "http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing" },
+            { "http://purl.oclc.org/ooxml/drawingml/wordprocessingDrawing", "http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing" },
+            { "http://purl.oclc.org/ooxml/officeDocument/bibliography", "http://schemas.openxmlformats.org/officeDocument/2006/bibliography" },
+            { "http://purl.oclc.org/ooxml/officeDocument/customProperties", "http://schemas.openxmlformats.org/officeDocument/2006/custom-properties" },
+            { "http://purl.oclc.org/ooxml/officeDocument/customXml", "http://schemas.openxmlformats.org/officeDocument/2006/customXml" },
+            { "http://purl.oclc.org/ooxml/officeDocument/customXmlDataProps", "http://schemas.openxmlformats.org/officeDocument/2006/customXmlDataProps" },
+            { "http://purl.oclc.org/ooxml/officeDocument/docPropsVTypes", "http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes" },
+            { "http://purl.oclc.org/ooxml/officeDocument/extendedProperties", "http://schemas.openxmlformats.org/officeDocument/2006/extended-properties" },
+            { "http://purl.oclc.org/ooxml/officeDocument/math", "http://schemas.openxmlformats.org/officeDocument/2006/math" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships", "http://schemas.openxmlformats.org/officeDocument/2006/relationships" },
+            { "http://purl.oclc.org/ooxml/presentationml/main", "http://schemas.openxmlformats.org/presentationml/2006/main" },
+            { "http://purl.oclc.org/ooxml/schemaLibrary/main", "http://schemas.openxmlformats.org/schemaLibrary/2006/main" },
+            { "http://purl.oclc.org/ooxml/spreadsheetml/main", "http://schemas.openxmlformats.org/spreadsheetml/2006/main" },
+            { "http://purl.oclc.org/ooxml/wordprocessingml/main", "http://schemas.openxmlformats.org/wordprocessingml/2006/main" },
+            { "http://purl.org/dc/dcmitype/", "http://purl.org/dc/dcmitype/" },
+            { "http://purl.org/dc/elements/1.1/", "http://purl.org/dc/elements/1.1/" },
+            { "http://purl.org/dc/terms/", "http://purl.org/dc/terms/" },
+            { "http://www.w3.org/2001/XMLSchema", "http://www.w3.org/2001/XMLSchema" },
+            { "http://www.w3.org/2001/XMLSchema-instance", "http://www.w3.org/2001/XMLSchema-instance" },
+            { "http://purl.oclc.org/ooxml/drawingml/lockedCanvas", "http://schemas.openxmlformats.org/drawingml/2006/lockedCanvas" },
+            { "http://purl.oclc.org/ooxml/drawingml/compatibility", "http://schemas.openxmlformats.org/drawingml/2006/compatibility" },
+            { "http://purl.oclc.org/ooxml/officeDocument/sharedTypes", "http://schemas.openxmlformats.org/officeDocument/2006/sharedTypes" },
+
+            // This is a namespace conversion. Workaround for a bug in ISO spec. https://www.assembla.com/code/IS29500/subversion/changesets/160
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/customXml", "http://schemas.openxmlformats.org/officeDocument/2006/customXml" },
+        };
+
+        // This dictionary contains the Strict and Transitional relationship pairs to be interpreted equivalent.
+        private static readonly Dictionary<string, string> _strictTransitionalRelationshipPairs = new Dictionary<string, string>(StringComparer.Ordinal)
+        {
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/aFChunk", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/aFChunk" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/attachedTemplate", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/attachedTemplate" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/audio", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/audio" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/calcChain", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/calcChain" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/chart", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/chart" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/chartsheet", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/chartsheet" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/chartUserShapes", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/chartUserShapes" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/commentAuthors", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/commentAuthors" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/comments", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/comments" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/connections", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/connections" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/control", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/control" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/customProperties", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/custom-properties" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/customProperty", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/customProperty" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/customXml", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/customXml" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/customXmlProps", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/customXmlProps" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/diagramColors", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/diagramColors" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/diagramData", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/diagramData" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/diagramLayout", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/diagramLayout" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/diagramQuickStyle", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/diagramQuickStyle" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/dialogsheet", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/dialogsheet" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/drawing", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/drawing" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/endnotes", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/endnotes" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/extendedProperties", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/externalLink", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/externalLink" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/externalLinkPath", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/externalLinkPath" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/font", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/font" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/fontTable", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/fontTable" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/footer", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/footer" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/footnotes", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/footnotes" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/frame", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/frame" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/glossaryDocument", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/glossaryDocument" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/handoutMaster", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/handoutMaster" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/header", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/header" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/htmlPubSaveAs", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/htmlPubSaveAs" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/hyperlink", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/image", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/mailMergeHeaderSource", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/mailMergeHeaderSource" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/mailMergeRecipientData", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/mailMergeRecipientData" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/mailMergeSource", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/mailMergeSource" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/metadata/thumbnail", "http://schemas.openxmlformats.org/package/2006/relationships/metadata/thumbnail" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/movie", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/movie" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/notesMaster", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/notesMaster" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/notesSlide", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/notesSlide" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/numbering", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/numbering" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/officeDocument", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/oleObject", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/oleObject" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/package", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/package" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/pivotCacheDefinition", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/pivotCacheDefinition" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/pivotCacheRecords", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/pivotCacheRecords" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/pivotTable", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/pivotTable" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/presProps", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/presProps" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/printerSettings", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/printerSettings" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/queryTable", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/queryTable" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/revisionHeaders", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/revisionHeaders" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/revisionLog", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/revisionLog" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/settings", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/settings" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/sharedStrings", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/sheetMetadata", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/sheetMetadata" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/slide", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slide" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/slideLayout", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideLayout" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/slideMaster", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideMaster" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/slideUpdateInfo", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideUpdateInfo" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/slideUpdateUrl", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slideUpdateUrl" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/styles", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/subDocument", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/subDocument" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/table", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/table" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/tableSingleCells", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/tableSingleCells" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/tableStyles", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/tableStyles" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/tags", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/tags" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/theme", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/theme" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/themeOverride", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/themeOverride" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/transform", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/transform" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/usernames", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/usernames" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/video", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/video" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/viewProps", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/viewProps" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/volatileDependencies", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/volatileDependencies" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/webSettings", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/webSettings" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/worksheet", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" },
+            { "http://purl.oclc.org/ooxml/officeDocument/relationships/xmlMaps", "http://schemas.openxmlformats.org/officeDocument/2006/relationships/xmlMaps" },
+        };
+
+        // The namespaces listed here are somewhat obsolete ones that we need to support. Before we try to get the index of a namespace,
+        // we check if it's in this list to rename to the expected correct namespace.
+        private static readonly Dictionary<string, string> _extendedNamespaces = new Dictionary<string, string>(StringComparer.Ordinal)
+        {
+            { "http://schemas.openxmlformats.org/wordprocessingml/2006/3/main", "http://schemas.openxmlformats.org/wordprocessingml/2006/main" },
+            { "http://schemas.openxmlformats.org/wordprocessingml/2006/5/main", "http://schemas.openxmlformats.org/wordprocessingml/2006/main" },
+            { "http://schemas.openxmlformats.org/wordprocessingml/2006/6/main", "http://schemas.openxmlformats.org/wordprocessingml/2006/main" },
+            { "http://schemas.openxmlformats.org/spreadsheetml/2006/5/main", "http://schemas.openxmlformats.org/spreadsheetml/2006/main" },
+            { "http://schemas.openxmlformats.org/spreadsheetml/2006/7/main", "http://schemas.openxmlformats.org/spreadsheetml/2006/main" },
+            { "http://schemas.openxmlformats.org/presentationml/2006/3/main", "http://schemas.openxmlformats.org/presentationml/2006/main" },
+            { "http://schemas.openxmlformats.org/drawingml/2006/3/main", "http://schemas.openxmlformats.org/drawingml/2006/main" },
+            { "http://schemas.microsoft.com/office/word/2010/11/wordml", "http://schemas.microsoft.com/office/word/2012/wordml" },
+        };
+
+        public static int Count => _namespaceResolver.Count;
+
+        /// <summary>
+        /// Attempts to get the Transitional equivalent namespace.
+        /// </summary>
+        /// <param name="strictNamespace">A namespace in Strict.</param>
+        /// <param name="transitionalNamespace">An equivalent namespace in Transitional.</param>
+        /// <returns>Returns true when a Transitional equivalent namespace is found, returns false when it is not found.</returns>
+        public static bool TryGetTransitionalNamespace(string strictNamespace, out string transitionalNamespace)
+        {
+            if (strictNamespace == null)
+            {
+                throw new ArgumentNullException(nameof(strictNamespace));
+            }
+
+            return _strictTransitionalNamespaces.TryGetValue(strictNamespace, out transitionalNamespace);
+        }
+
+        /// <summary>
+        /// Attempts to get the Transitional equivalent relationship.
+        /// </summary>
+        /// <param name="strictRelationship">A relationship in Strict.</param>
+        /// <param name="transitionalRelationship">An equivalent relationship in Transitional.</param>
+        /// <returns>Returns true when a Transitional equivalent relationship is found, returns false when it is not.</returns>
+        public static bool TryGetTransitionalRelationship(string strictRelationship, out string transitionalRelationship)
+        {
+            if (strictRelationship == null)
+            {
+                throw new ArgumentNullException(nameof(strictRelationship));
+            }
+
+            return _strictTransitionalRelationshipPairs.TryGetValue(strictRelationship, out transitionalRelationship);
+        }
+
+        public static bool IsInFileFormat(string ns, FileFormatVersions format)
+        {
+            if (_namespaceResolver.TryGetByNamespace(ns, out var info))
+            {
+                return info.Version == format;
+            }
+
+            return false;
+        }
+
+        public static byte GetNamespaceId(string namespaceUri)
+        {
+            if (TryGetNamespaceId(namespaceUri, out var id))
+            {
+                return id;
+            }
+
+            throw new KeyNotFoundException();
+        }
+
+        public static bool TryGetNamespaceId(string namespaceUri, out byte id)
+        {
+            if (namespaceUri != null && _namespaceResolver.TryGetByNamespace(NormalizeNamespace(namespaceUri), out var info))
+            {
+                id = info.Id;
+                return true;
+            }
+            else
+            {
+                id = byte.MaxValue;
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Gets the namespace URI for the specified namespace ID.
+        /// </summary>
+        /// <param name="namespaceId">The namespace ID.</param>
+        /// <returns></returns>
+        public static string GetNamespaceUri(byte namespaceId) => _namespaceResolver[namespaceId].Namespace;
+
+        /// <summary>
+        /// Gets the namespace URI for the specified namespace prefix.
+        /// </summary>
+        /// <param name="prefix">The namespace prefix.</param>
+        /// <returns></returns>
+        public static string GetNamespaceUri(string prefix)
+        {
+            if (prefix == null)
+            {
+                throw new ArgumentNullException(nameof(prefix));
+            }
+
+            if (_namespaceResolver.TryGetByPrefix(prefix, out var info))
+            {
+                return info.Namespace;
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Gets the default namespace prefix for the specified namespace ID.
+        /// </summary>
+        /// <param name="namespaceId">The namespace ID.</param>
+        /// <returns></returns>
+        public static string GetNamespacePrefix(byte namespaceId) => _namespaceResolver[namespaceId].Prefix;
+
+        public static string GetNamespacePrefix(string namespaceUri) => _namespaceResolver.TryGetByNamespace(namespaceUri, out var info) ? info.Prefix : null;
+
+        /// <summary>
+        /// Try to get the expected namespace if the passed namespace is an obsolete.
+        /// </summary>
+        /// <param name="namespaceUri">The namespace to pass.</param>
+        /// <param name="extNamespaceUri">The expected namespace when the passed namespace is an obsolete.</param>
+        /// <returns>True when the passed namespace is an obsolete and the expected namespace found</returns>
+        public static bool TryGetExtendedNamespace(string namespaceUri, out string extNamespaceUri)
+        {
+            return _extendedNamespaces.TryGetValue(namespaceUri, out extNamespaceUri);
+        }
+
+        private static string NormalizeNamespace(string ns)
+        {
+            if (_extendedNamespaces.TryGetValue(ns, out var result))
+            {
+                return result;
+            }
+
+            return ns;
+        }
+
+        private class NamespaceResolver : IEnumerable
+        {
+            private readonly Dictionary<string, NamespaceInfo> _byNamespace = new Dictionary<string, NamespaceInfo>(StringComparer.Ordinal);
+            private readonly Dictionary<string, NamespaceInfo> _byPrefix = new Dictionary<string, NamespaceInfo>(StringComparer.Ordinal);
+            private readonly List<NamespaceInfo> _info = new List<NamespaceInfo>();
+
+            public int Count => _info.Count;
+
+            public void Add(string @namespace, string prefix, FileFormatVersions version)
+            {
+                var info = new NamespaceInfo(@namespace, prefix, version, (byte)_info.Count);
+
+                _byNamespace.Add(@namespace, info);
+                _byPrefix.Add(prefix, info);
+                _info.Add(info);
+            }
+
+            public NamespaceInfo this[int id] => _info[id];
+
+            public bool TryGetByNamespace(string ns, out NamespaceInfo info) => _byNamespace.TryGetValue(ns, out info);
+
+            public bool TryGetByPrefix(string prefix, out NamespaceInfo info) => _byPrefix.TryGetValue(prefix, out info);
+
+            IEnumerator IEnumerable.GetEnumerator() => _info.GetEnumerator();
+
+            public class NamespaceInfo
+            {
+                public NamespaceInfo(string ns, string prefix, FileFormatVersions version, byte id)
+                {
+                    Namespace = ns;
+                    Prefix = prefix;
+                    Version = version;
+                    Id = id;
+                }
+
+                public string Namespace { get; }
+
+                public string Prefix { get; }
+
+                public FileFormatVersions Version { get; }
+
+                public byte Id { get; }
+            }
+        }
+    }
+}